Scientists Discover New Nerve Cell Characteristic

January 18, 2006

By Lori Jennings

Giorgio Ascoli Creative Services photo

George Mason scientists Giorgio Ascoli and Alexei Samsonovich in the Krasnow Institute for Advanced Study announced their joint discovery of a new form of nerve cell homeostasis, or state of equilibrium. The findings, applied to mammalian nerve cells, have potential implications in the study and treatment of common debilitating diseases such as epilepsy, Alzheimer’s and Parkinson’s, as well as development and aging.

Ascoli and Samsonovich’s findings are available online at www.pnas.org. They will be published in the Proceedings of the National Academy of Sciences of the United States of America’s Jan. 31 journal article titled “Morphological Homeostasis in Cortical Dendrites.”

The researchers discovered that the anatomical structure of nerve cells is under homeostatic control, meaning that if one portion of a nerve cell is larger than average, another portion of the same cell will be smaller. This finding is unexpected in that the opposite is true in other natural systems (for example, people with larger hands also tend to have larger, not smaller, feet). Ascoli and Samsonovich proposed an explanation of their discovery based on cellular competition for limited resources.

“We are cautiously optimistic at this stage that these results will have a significant impact on the field of neuroscience and the study of developing, damaged or mutated nerve structures,” says Ascoli.

“This finding helps us better understand how our brain is organized from a structural perspective – how our cells arrange themselves to optimize the limited resources available inside our skulls. This quantitative description will eventually allow us to better understand and even treat diseases like epilepsy, Alzheimer’s and Parkinson’s.

“Additionally, this discovery has applications to the study of development and aging and the insertion of maturing neural stem cells in adult brain tissue.”

Ascoli and Samsonovich related their investigation to the widely accepted principle that physiological homeostasis, including the internal control of electrical activity, metabolism and other neurological functions, is critical to the overall functioning of the brain. The researchers’ discovery demonstrates a new and fundamental form of homeostasis, namely the regulation of the very size of nerve cells in the mammalian cortex.

Ascoli is a professor with Krasnow and the Department of Psychology. During his time at the university, he has received approximately $3.5 million in active, multi-year research grants. Ascoli’s grant work focuses on the development and application of new computational techniques to investigate how the complex morphology of nerve cells enables their function.

He is also working on understanding how the changes of neuronal anatomy similar to those occurring in Alzheimer’s patients may cause the impaired behavior of nerve cells at the basis of memory loss and dementia. His research may shed light on the basic mechanisms underlying the neuronal malfunction that typifies Alzheimer’s and related diseases.

Samsonovich is a postdoctoral researcher in Ascoli’s laboratory. His work focuses on computational and cognitive neuroscience.

Return to Main Gazette Page